The present invention relates to a method of conserving electric power in a wireless local area network (LAN). More specifically, the present invention relates to a technology for reducing power consumption of a mobile terminal device with a battery as a power source. Patent Reference 1; Japanese Patent Publication (Kokai) No. 11-313370
FIG. 2 shows a conventional mobile bucket communication system disclosed in Patent Reference 1. In the mobile bucket communication system, while a connection (SVC; Switching Virtual Circuit) is established between a mobile terminal device PS1 and a gateway GW, a timer disposed in the mobile terminal device PS1 as a timing device watches a period of time when data communication is not performed. When the data communication is not performed for a specific period of time, the mobile terminal device PS1 sends a sleep notice to the gateway GW. Accordingly, the connection between the devices is disconnected, and the mobile terminal device PS1 becomes a sleep state.
After the connection is disconnected, when it is necessary to send bucket data through the connection, the connection is re-connected according to routing information stored when the connection is originally established. Accordingly, when the data communication is not performed for a specific period of time, the mobile terminal device PS1 becomes the sleep state, thereby reducing power consumption.
In Patent Reference 1, no specific numerical example has been disclosed regarding how long the timer watches for switching the mobile terminal device PS1 to the sleep state. Every time the mobile terminal device PS1 is switched to the sleep state, it is necessary to disconnect and reset the connection. Accordingly, it is difficult to set the timer to watch for a long period of time considering transfer efficiency and an influence of a load on the gateway GW. As a result, it is difficult to reduce power consumption to a large extent through switching the mobile terminal device PS1 to the sleep state.
In view of the problems described above, an object of the present invention is to provide a method of conserving electric power in a wireless LAN to a large extent.
Further, in the conventional technology, when power is conserved, a liquid crystal display becomes dim or a response is slowed, thereby causing inconvenience to a user using a browser. Accordingly, another object of the present invention is to provide a method of conserving power of a mobile terminal device upon communication without causing such inconvenience.
Further objects and advantages of the invention will be apparent from the following description of the invention.